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What book on Voyager were you referencing? In any case, they started developing the Voyager spacecraft in the 1960's. The first measurement that a solar wind even existed wasn't reported until 1960-1961 [K. Gringauz using the Lunik 2 spacecraft]. They were able to determine a flux of particles (i.e., number per area per time), but did not determine speed ...

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Plasma potential. Often electrons move faster than ions and leave the plasma at a higher rate. The plasma becomes positive until the positive 'plasmas potential' slows down the rate of electron loss from the plasma until it is the same as the rate of positive ion loss. The electrons are partially held in the plasma by the attractive positive plasma ...

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If the number of electrons and ions is exactly equal, it is still plasma. You are misunderstanding the quasineutrality requirement. The term "plasma" was coined by Irving Langmuir with the phrase "We shall use the name plasma to describe this region containing balanced charges of ions and electrons", Oscillations in Ionized Gases Proc. Nat. Acad. Sci. ...

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Note that plasma oscillations in the long wavelength limit are due to the restoring force originated in the attraction between positive and negative charges. When only like charges exist, such oscillations tend to disappear. See the book by Ashcroft and Mermin.

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Consider a plasma that just's been formed and then left alone. Being far from equilibrium, the plasma will evolve towards an equilibrium state. At this stage, it's not very useful to characterize the plasma with a temperature because the velocity distribution would bear little resemblance to a Boltzmann distribution, or really any kind of distribution ...

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There are lots of different types of plasmas. In a thermal plasma the electrons and ions will have the same temperature. In a non-thermal plasma the discharge is driven by some external power supply e.g. capacitatively coupled RF, inductively coupled, pulsed DC E field etc. In a non-thermal plasma the electrons generally have a higher temperature than ...

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The radiation belts are thought to be produced through multiple processes. One of the original leading ideas was the concept of radial diffusion. Other ideas included energization due to low frequency waves. I have done work in this field, but only with a higher frequency electromagnetic wave called whistler mode waves. I will focus on these in my ...

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Plasma is when the electrons are "freed" from their host atoms for a short time, due to high temperatures. Fire is plasma, it responds to electric fields. Lightning is also plasma. When a column of electrons flows from sky to ground, the air that it passes through lights up with energy. What we see as lightning is actually the air where the electrons are at, ...

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Very high temperature, on the order of 10 keV, is needed for fusion reactions to start to happen at appreciable rates. However, in magnetic fusion devices (tokamak, stellarator) the transport of heat across the plasma (due to plasma turbulence) causes heat losses. Making the system larger allows increasing the heating power (due to fusion reactions, plasma ...

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The motivation for pursuing fusion is clear, but there are currently several main physics and engineering challenges: Confinement time: An operational reactor requires a long energy confinement time, $\tau_E$. An empirical scaling law for confinement time has been found to depend on the size of the tokamak as $\tau_E \propto R^{2.04} a^{1.04}$, where $R$ ...

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Well, I am not sure if your statements are entirely accurate because the fast mode can approach the lower hybrid resonance. In fact, in this regime, it becomes effectively indistinguishable from an electrostatic whistler mode. At low frequency and oblique angles, the fast (or magnetosonic) modes are right-hand polarized (with respect to $\mathbf{B}_{o}$) ...

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First Question Well, the first thing is that $J$ = $\sigma \ E$ happens to be an approximation (fun side note: there is no general derivation of Ohm's law from first principles [at least that's what J.D. Jackson argues]). The conductivity is actually a tensor, which contains parts similar to your expression for epsilon. In and wave plasma theory, one ...

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